Linux Terminal Command: at

The at command is an essential tool in System Services & Scheduling. In this tutorial, we will explore what at does, look at everyday examples, and cover advanced options to supercharge your command-line workflow.

Concept & Explanation

The at command schedules tasks to run exactly once at a specified time.

Common Options & Syntax

at [options] [arguments]

Here are the most common flags used with at:

• Simple Usage: Basic default commands.
• Detailed View: Shows diagnostic information.
• Advanced Actions: Can chain parameters for scripting.

1. Interactive Example (Simple)

Here is how most people run the command:

# Example
echo 'tar -czf backup.tar.gz ./files' | at 23:00

What it does: Schedules a backup to run exactly once at 11:00 PM.

2. Power-User Example (Advanced)

For scripting and advanced diagnostics, use this configuration:

# Advanced
atq && atrm 5

What it does: Lists the active queue of pending jobs (atq) and deletes job ID 5 (atrm).

⚙️ Warning & Common Pitfalls

[!WARNING] The at command requires the atd daemon to be active. If the service is stopped, scheduled jobs will not execute.

🔗 Related Commands

Here are some related posts on cli_tty1 you might want to check out:

• jobs : List active shell jobs.